Many batteries on new vehicles are mounted inside under the back seat, but we don't have that option here. If bucket seat are being used, the battery can fit between them at the rear of the cab. The batteries used are AGM that still can produce gases during charge, but use a hose attachment on top of case ends to exit under vehicle. Regardless what battery is used, placing it inside for the most part (Off Road is Still Off Road), place the battery away from vibration and heat. Both will damage internal cell connections due to expansion and contraction, while vibration speaks for itself. Vehicles with rear seat mount batteries are lasting over 10 years or more over normal service.
Using high grade larger cabling thru floor holes need protection using rubber grommets and should provide absolute ground connections to engine, alternator, frame, bed and cab. The OEM bare straps corrode over time and connections can have high resistance. I can change mine with soldiered lugs, shrink wrap tubing, "Star" washers and dielectric grease. "Star" washer will help cut thru power coat, rust, grease and paint to provide a low resistant confirmed with current on and voltage drop testing.
A company called "Knuknocepts.com" cater to audio installs, but also mobile / marine as well.
They sell unique battery clamps that fit top post terminals exactly as they are tapered. Look at P/N UBT-840P for B+ & UBT-840N for negative. They use allan wrench fittings and you can fit 1/0, 4, 8 gauge wire with add-ons. They are $14.99 each with color coded plastic covers where holes can be placed for wire placement. They are excellent for the price.
They sell wire that the high end stuff is tinned oxygen free copper wire with high stand count making them extremely flexible, from 4/0 up gauge flexible cabling is sold per the foot also. 1/0 wire will carry 375 amps over 20 ft with a 12mm core. The 4/0 (0000) wire will carry 600 amps over 20 foot with a 18mm core. $3.50 per ft up to $6.09 per ft.
if you are interested.
